CN101231412A - Backlight tube open circuit and short-circuit protection circuit - Google Patents
Backlight tube open circuit and short-circuit protection circuit Download PDFInfo
- Publication number
- CN101231412A CN101231412A CNA2007100731280A CN200710073128A CN101231412A CN 101231412 A CN101231412 A CN 101231412A CN A2007100731280 A CNA2007100731280 A CN A2007100731280A CN 200710073128 A CN200710073128 A CN 200710073128A CN 101231412 A CN101231412 A CN 101231412A
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- China
- Prior art keywords
- circuit
- short
- backlight
- tube open
- microcontroller
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
- H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
- H05B41/2821—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a single-switch converter or a parallel push-pull converter in the final stage
- H05B41/2824—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices by means of a single-switch converter or a parallel push-pull converter in the final stage using control circuits for the switching element
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/36—Controlling
- H05B41/38—Controlling the intensity of light
- H05B41/39—Controlling the intensity of light continuously
- H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
- H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
- H05B41/3927—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by pulse width modulation
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
Landscapes
- Circuit Arrangements For Discharge Lamps (AREA)
Abstract
The invention provides a protective circuit for the open-circuit/short-circuit with a backlight lamp, which comprises at least one detection circuit, a pulse width modulation integrated circuit and a microcontroller. Each detection circuit comprises one backlight lamp. The detection circuit outputs the relevant voltage signal to the microcontroller according to the working state of the backlight lamp. The microcontroller outputs the relevant control signal to control the working state of the pulse width modulation integrated circuit.
Description
Technical field
The present invention relates to a kind of backlight tube open circuit and short-circuit protection circuit, relate in particular to a kind of backlight tube open circuit and short-circuit protection circuit that is used for liquid crystal indicator.
Background technology
Liquid crystal indicator has characteristics such as low diathermaneity, compact and power consumption are low because of it, and is therefore day by day extensive in the use, and along with the ripe and innovation of correlation technique, its kind is also various day by day.Because the liquid crystal molecule itself in the liquid crystal indicator is not luminous; therefore liquid crystal indicator needs to show by the luminous image of realizing of a module backlight; common module backlight comprises a plurality of backlight lamp tubes; safety for the high-voltage inverter (Inverter) that this a plurality of backlight lamp tube connected has high requirements; in order to prevent that operating personnel are under operation lack of standardization or accident; with backlight lamp tube short circuit or open circuit; guaranteeing also will to protect when operating personnel preserve from of liquid crystal indicator itself, therefore need be in high-voltage inverter the design protection circuit.
See also Fig. 1, it is the synoptic diagram of a kind of prior art backlight tube open circuit and short-circuit protection circuit 100.This backlight tube open circuit and short-circuit protection circuit 100 comprise four testing circuits 110, an input circuit 130, a pulse-width modulation integrated circuit 150 and an on-off circuit 170.
Each testing circuit 110 comprises that a backlight lamp tube 111, detects an output terminal 112 and a current rectifying and wave filtering circuit 113, and each backlight lamp tube 111 connects one by a current rectifying and wave filtering circuit 113 and detects output terminal 112.
This input circuit 130 comprises four diodes 131, four biasing resistors 132, four filter capacitors 135, a first transistor 1331, a transistor seconds 1332, one the 3rd transistor 1333 and one the 4th transistor 1334.The source ground of this first transistor 1331, the drain electrode of this first transistor 1331 is electrically connected to the source electrode of this transistor seconds 1332, the drain electrode of this transistor seconds 1332 is electrically connected to the source electrode of the 3rd transistor 1333, the drain electrode of the 3rd transistor 1333 is electrically connected to the source electrode of the 4th transistor 1334, and the drain electrode of the 4th transistor 1334 is output terminals of this input circuit 130.By a biasing resistor 132 and a filter capacitor 135 ground connection, this biasing resistor 132 and this filter capacitor 135 are connected in parallel the grid of the first transistor 1331 respectively.The negative electricity of one diode 131 is connected to the grid of this first transistor 1331, and the positive pole of this diode 131 is as an input end of this input circuit 130.The grid syndeton of this transistor seconds 1332, the 3rd transistor 1333 and the 4th transistor 1334 is identical with the grid syndeton of this first transistor 1331.The positive pole of this four diode 131 is respectively as the four-input terminal of this input circuit 130.
This pulse-width modulation integrated circuit 150 comprises a current sample end 151, and when this current sample end 151 was drawn to low-voltage, this pulse-width modulation integrated circuit 150 quit work.
This on-off circuit 170 comprises one the 5th transistor 171, first, second current-limiting resistance 172,173 and an output terminal 175, the source ground of the 5th transistor 171, the drain electrode of the 5th transistor 171 is electrically connected to the current sample end 151 of this pulse-width modulation integrated circuit 150, and connect this output terminal 175 by this second current-limiting resistance 173, this output terminal 175 inputs one high voltage, the drain electrode of the grid of the 5th transistor 171 and the 4th transistor 1334 is electrically connected to a power vd D (voltage is 5 volts) by this first current-limiting resistance 172 simultaneously.
During operate as normal, four of this four testing circuit 110 detects output terminal 112 and all exports four high voltage signals.This four high voltage signal makes this first transistor 1331 through this four diode 131, transistor seconds 1332, the 3rd transistor 1333 and the 4th transistor 1334 are all opened, the drain electrode of the 4th transistor 1334 by drop-down be low-voltage, promptly this power vd D is by this current-limiting resistance 172, this the first transistor 1331, transistor seconds 1332, the 3rd transistor 1333 and the 4th transistor 1334 ground connection, so the grid of the 5th transistor 171 input low-voltage, the 5th transistor 171 is closed, because of this output terminal 175 inputs one high voltage, so the current sample end 151 of this pulse-width modulation integrated circuit 150 is a high voltage, this pulse-width modulation integrated circuit 150 is in normal operating conditions.
When any testing circuit 110 detects a certain backlight lamp tube 111 for open circuit or short circuit, the detection output terminal 112 of this testing circuit 110 produces a low voltage signal, this low voltage signal makes one of this first transistor 1331, transistor seconds 1332, the 3rd transistor 1333 and the 4th transistor 1334 close by corresponding diode 131, because the drain electrode of the grid of the 5th transistor 171 and the 4th transistor 1334 is electrically connected this power vd D by this first current-limiting resistance 172 simultaneously.Therefore the grid of the 5th transistor 171 is a high voltage; the 5th transistor 171 is opened; drawn and be low-voltage so be connected this current sample end 151 in the drain electrode of the 5th transistor 171, this pulse-width modulation integrated circuit 150 quits work, and realizes backlight tube open circuit and short-circuit protection function.
This backlight tube open circuit and short-circuit protection circuit 100 need an input circuit 130 and an on-off circuit 170 to feed back the output signal of this testing circuit 110 to realize backlight tube open circuit and short-circuit protection function.This input circuit 130 comprises a plurality of transistors; when if the backlight lamp tube of this backlight tube open circuit and short-circuit protection circuit 100 further increases; the transistor of this input circuit 130 also needs corresponding increase, thereby the change of the circuit structure of this backlight tube open circuit and short-circuit protection circuit 100 is higher than complexity and cost.
Summary of the invention
In order to solve backlight tube open circuit and short-circuit protection circuit complex structure and the high problem of cost in the prior art, the invention provides a kind of simple in structure and lower-cost backlight tube open circuit and short-circuit protection circuit.
A kind of backlight tube open circuit and short-circuit protection circuit, it comprises at least one testing circuit, a pulse-width modulation integrated circuit and a microcontroller, each testing circuit comprises a backlight lamp tube.This testing circuit is exported the correspondent voltage signal to this microcontroller according to the duty of backlight lamp tube, and this microcontroller output control signal corresponding is to control the duty of this pulse-width modulation integrated circuit.
Compared with prior art; backlight tube open circuit of the present invention and short-circuit protection circuit feed back the output signal of this testing circuit with a microcontroller; thereby realize backlight tube open circuit and short-circuit protection function, so the circuit structure of this backlight tube open circuit and short-circuit protection circuit is simple.When this backlight tube open circuit and short-circuit protection circuit are applied in the electronic products such as liquid crystal indicator; these electronic products itself have microcontroller; therefore this backlight tube open circuit and short-circuit protection circuit can directly utilize this microcontroller, thereby can save the cost of electronic product.
Description of drawings
Fig. 1 is the synoptic diagram of a kind of prior art backlight tube open circuit and open loop protection circuit.
Fig. 2 is the synoptic diagram of backlight tube open circuit of the present invention and short-circuit protection circuit.
Embodiment
See also Fig. 2, it is the synoptic diagram of backlight tube open circuit of the present invention and short-circuit protection circuit 200.This backlight tube open circuit and short-circuit protection circuit 200 comprise four testing circuits 210, a pulse-width modulation integrated circuit 250 and a microcontroller 260.
Each testing circuit 210 comprises that a backlight lamp tube 211, detects an output terminal 212 and a current rectifying and wave filtering circuit 213, and each backlight lamp tube 211 connects one by a current rectifying and wave filtering circuit 213 and detects output terminal 212.
This pulse-width modulation integrated circuit 250 comprises a current sample end 251, and when this current sample end 251 was drawn to low-voltage, this pulse-width modulation integrated circuit 250 quit work.
This microcontroller 260 comprises a plurality of analog to digital conversion input end ADC1～ADCn and an output terminal I/O, each analog to digital conversion input end is electrically connected with the detection output terminal 212 of a testing circuit 210, and this output terminal I/O is electrically connected with the current sample end 251 of this pulse-width modulation integrated circuit 250.By software this microcontroller 260 is done following setting: when the input signal of each analog to digital conversion input end ADC1～ADCn all was high level, this output terminal I/O continued the output high level; When the input signal of arbitrary analog to digital conversion input end was low level, this output terminal I/O exported a low level.
During operate as normal, four of this four testing circuit 210 detects output terminal 212 and all exports four high voltage signals.This four high voltage signal inputs to the analog to digital conversion input end ADC1～ADC4 of this microcontroller 260 respectively, and this output terminal I/O is output as high level.This high level signal inputs to the current sample end 251 of this pulse-width modulation integrated circuit 250, and this pulse-width modulation integrated circuit 250 is in normal operating conditions.
When any backlight lamp tube 211 is open circuit or short circuit, the detection output terminal 212 of its corresponding testing circuit 210 produces a low voltage signal, this low voltage signal inputs to the corresponding analog to digital conversion input end of this microcontroller 260, and this output terminal I/O output becomes low level.This low level signal inputs to the current sample end 251 of this pulse-width modulation integrated circuit 250, and this pulse-width modulation integrated circuit 250 quits work, thereby realizes backlight tube open circuit and short-circuit protection function.
This backlight tube open circuit and short-circuit protection circuit 200 are suitable for backlight lamp tube 211 simultaneously and are less than four situation.
When the number of backlight lamp tube 211 increases,, be connected with the idle analog to digital conversion input end of this microcontroller 260 and get final product so the correspondence of the backlight lamp tube that increases is detected output terminal because of this microcontroller 260 has more idle analog to digital conversion input end.
Compared with prior art; the output signal of backlight tube open circuit of the present invention and short-circuit protection circuit 200 usefulness one microcontroller 260 these testing circuits 210 of feedback; thereby realize backlight tube open circuit and short-circuit protection function, so the circuit structure of this backlight tube open circuit and short-circuit protection circuit 200 is simple.When this backlight tube open circuit and short-circuit protection circuit 200 are applied in the electronic products such as liquid crystal indicator; these electronic products itself have microcontroller; therefore this backlight tube open circuit and short-circuit protection circuit 200 can directly utilize this microcontroller, thereby can save the cost of electronic product.
Claims (6)
1. backlight tube open circuit and short-circuit protection circuit; it comprises an at least one testing circuit and a pulse-width modulation integrated circuit; each testing circuit comprises a backlight lamp tube; it is characterized in that: this backlight tube open circuit and short-circuit protection circuit also comprise a microcontroller; this testing circuit is exported the correspondent voltage signal to this microcontroller according to the duty of backlight lamp tube, and this microcontroller output control signal corresponding is to control the duty of this pulse-width modulation integrated circuit.
2. backlight tube open circuit as claimed in claim 1 and short-circuit protection circuit is characterized in that: each testing circuit comprises that also one detects an output terminal and a current rectifying and wave filtering circuit, and each backlight lamp tube connects one by a current rectifying and wave filtering circuit and detects output terminal.
3. backlight tube open circuit as claimed in claim 2 and short-circuit protection circuit is characterized in that: this microcontroller comprises a plurality of analog to digital conversion input ends and an output terminal, and each analog to digital conversion input end is electrically connected with the detection output terminal of a testing circuit.
4. backlight tube open circuit as claimed in claim 3 and short-circuit protection circuit is characterized in that: this pulse-width modulation integrated circuit comprises a current sample end, and this current sample end is electrically connected with the output terminal of this microcontroller.
5. backlight tube open circuit as claimed in claim 4 and short-circuit protection circuit; it is characterized in that: when the input signal of arbitrary analog to digital conversion input end of this microcontroller is low level; its output terminal is exported a low level; when the current sample end of this pulse-width modulation integrated circuit was drawn to low-voltage, this pulse-width modulation integrated circuit quit work.
6. backlight tube open circuit as claimed in claim 1 and short-circuit protection circuit is characterized in that: the number of this testing circuit is four.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007100731280A CN101231412B (en) | 2007-01-26 | 2007-01-26 | Backlight tube open circuit and short-circuit protection circuit |
| US12/011,696 US7843151B2 (en) | 2007-01-26 | 2008-01-28 | Backlight control circuit with micro controller feeding operating state of load circuit back to pulse width modulation integrated circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2007100731280A CN101231412B (en) | 2007-01-26 | 2007-01-26 | Backlight tube open circuit and short-circuit protection circuit |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101231412A true CN101231412A (en) | 2008-07-30 |
| CN101231412B CN101231412B (en) | 2011-12-07 |
Family
ID=39667192
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2007100731280A Expired - Fee Related CN101231412B (en) | 2007-01-26 | 2007-01-26 | Backlight tube open circuit and short-circuit protection circuit |
Country Status (2)
| Country | Link |
|---|---|
| US (1) | US7843151B2 (en) |
| CN (1) | CN101231412B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106448564A (en) * | 2016-12-20 | 2017-02-22 | 京东方科技集团股份有限公司 | OLED pixel circuit as well as driving method and display device thereof |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20110025233A1 (en) * | 2008-04-14 | 2011-02-03 | Morales Louis J | Method and Apparatus For Reduction of Excess Current During Initial Firing of Arc Lamp Circuits |
| CN101620829B (en) * | 2008-07-04 | 2012-02-08 | 群康科技(深圳)有限公司 | Backlight protective circuit |
| TWI460704B (en) * | 2012-03-21 | 2014-11-11 | Innocom Tech Shenzhen Co Ltd | Display and driving method thereof |
| CN103063975A (en) * | 2012-12-26 | 2013-04-24 | 成都市中州半导体科技有限公司 | Open circuit and short circuit testing system and method |
| CN115436777B (en) * | 2022-08-11 | 2024-09-10 | 江西晶浩光学有限公司 | Open-short circuit testing device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5339009A (en) * | 1991-08-08 | 1994-08-16 | Ford Motor Company | Method and apparatus for distinguishing input signals and generating a common dimming signal |
| US5923129A (en) * | 1997-03-14 | 1999-07-13 | Linfinity Microelectronics | Apparatus and method for starting a fluorescent lamp |
| US6376999B1 (en) * | 2000-09-15 | 2002-04-23 | Philips Electronics North America Corporation | Electronic ballast employing a startup transient voltage suppression circuit |
| KR100401100B1 (en) * | 2000-11-22 | 2003-10-10 | 삼성전기주식회사 | Back-light inverter of LCD |
| US6504321B2 (en) * | 2001-02-06 | 2003-01-07 | Koninklijke Philips Electronics N.V. | Universal hardware/software feedback control for high-frequency signals |
| US6674379B1 (en) * | 2002-09-30 | 2004-01-06 | Koninklijke Philips Electronics N.V. | Digital controller with two control paths |
| TWI333187B (en) * | 2004-07-09 | 2010-11-11 | Hon Hai Prec Ind Co Ltd | Apparatus and method for prolonging lamp life |
| CN1738125A (en) * | 2004-09-01 | 2006-02-22 | 兰州大成自动化工程有限公司 | Electronic overcurrent protection device using microcontroller for control |
| CN100443994C (en) * | 2005-06-17 | 2008-12-17 | 群康科技(深圳)有限公司 | Backlight open circuit protection circuit |
| TW200723196A (en) * | 2005-12-01 | 2007-06-16 | Holtek Semiconductor Inc | Driving control circuit and method for cold cathode fluorescent lamp |
| KR101300007B1 (en) * | 2006-02-10 | 2013-08-27 | 필립스 솔리드-스테이트 라이팅 솔루션스, 인크. | Methods and apparatus for high power factor controlled power delivery using a single switching stage per load |
| TW200844928A (en) * | 2007-05-02 | 2008-11-16 | Novatek Microelectronics Corp | Apparatus for controlling brightness of light source and displaying apparatus |
-
2007
- 2007-01-26 CN CN2007100731280A patent/CN101231412B/en not_active Expired - Fee Related
-
2008
- 2008-01-28 US US12/011,696 patent/US7843151B2/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106448564A (en) * | 2016-12-20 | 2017-02-22 | 京东方科技集团股份有限公司 | OLED pixel circuit as well as driving method and display device thereof |
| CN106448564B (en) * | 2016-12-20 | 2019-06-25 | 京东方科技集团股份有限公司 | A kind of OLED pixel circuit and its driving method, display device |
| US10380946B2 (en) | 2016-12-20 | 2019-08-13 | Boe Technology Group Co., Ltd. | OLED pixel circuitry, driving method thereof and display device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101231412B (en) | 2011-12-07 |
| US20080180038A1 (en) | 2008-07-31 |
| US7843151B2 (en) | 2010-11-30 |
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Granted publication date: 20111207 Termination date: 20190126 |
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| CF01 | Termination of patent right due to non-payment of annual fee |